Puppy regression because of pregnancy?

We adopted a puppy nearly 4 months ago...he's now about 6-7 months old. His name is Draxx 💜 He's been a typical hound dog puppy with a lot of barking and stuff and has been completely housebroken. We found out that I'm pregnant about a week and a half ago and since then, he's regressed. He is popping in the house, nearly exclusively. We walk him like 7-10 times a day, no joke, and he's totally disinterested in pooping outside; then within the next few moments, he poops somewhere in the house. He's even pooping in his crate (twice this week!) It's so frustrating and we're literally cleaning up poop a jillion times a day and thru out the nite (last nite, he pooped in the house at 145am, 530am and again at 9am). Being newly pregnant, it's absolutely exhausting and nauseating, and I don't think I can handle this for the next several months! My husband is losing his patience and starting to ask questions about whether or not he's the right fit for our family.

I took him to the vet last Sunday and had another fecal exam done and he got a clean bill of health. His diet hasn't changed either. My brother's husky puppy was over last weekend and she had some accidents in the house (I think she got sick eating our dog's food), so maybe it's like an adjustment or something from her being gone? We also have an 8 year old dog who is amazing, but the last week or 2, she's wanting nothing to do with our puppy.

Help, please!